This invention relates to oxazolidone-containing polymers and more particularly to their preparation from storage-stable one-package compositions.
Interest in high molecular weight polyoxazolidones has increased recently because of the high temperature resistance of these polymers. Several methods for preparing oxazolidones are known but many of these are not practical because of the high cost of preparation of reactants suitable for use in producing high molecular weight polyoxazolidones. The preparation of 2-oxazolidones is reviewed by Dyen and Swern in Chemical Revisions, vol. 67, 1967, pp. 197-246. Ashida and Frisch, in the Journal of Cellular Plastics, July/August, 1972, pp. 194-200, discuss the preparation of oxazolidone modified isocyanurate foams by the reaction of phenyl isocyanate and phenyl glycidyl ether. Dileone in Journal of Polymer Science, vol. 8, 1970, pp. 609-615 discusses the synthesis of poly 2-oxazolidones from diisocyanates and diepoxides.
The preparation of oxazolidone group-containing polymers by reaction of isocyanates and epoxides is of interest because of the possibility of forming various polymeric systems by varying the functionality and relative concentrations of the reactants and by including other components in the reaction mixture. For example, very high molecular weight thermoplastic polymers can be prepared from difunctional reactants whereas highly crosslinked polymers can be prepared from reactants having more than two functional groups per molecule. The latter are excellent for preparing polymeric foams. By varying the ratio of isocyanate groups to epoxy groups, oxazolidone-containing isocyanurate polymers, polyoxazolidones or oxazolidone-containing polyether compounds can be prepared. By including polyol, polyamine or polythiol components in the formulation, polyoxazolidone-containing urethane urea or thiourethane polymers can be prepared.
The use of isocyanates in the preparation of oxazolidone-containing polymers or storage-stable oxazolidone-forming compositions is undesirable because of the highly toxic nature of isocyanates, particularly aliphatic isocyanates, from which ultraviolet light-stable compounds are prepared. Furthermore, because of their great reactivity with epoxides, alcohols, and water, they do not readily lend themselves to one package storage-stable polyoxazolidone-forming systems. Because of the disadvantages of using isocyanates in the preparation of oxazolidone-containing polymers, improved epoxide-containing systems are constantly being sought which have good storage stability and which produce superior polyoxazolidone compositions.
A polyoxazolidone-forming system having good storage stability and which produces a superior oxazolidone-containing polymer of the above-described character has now been discovered.
Accordingly, it is one object of the invention to present an improved method of preparing oxazolidone-modified polymers. It is another object of the invention to present a new method of preparing oxazolidone-modified polymers from epoxides. It is another object of the invention to present a method of preparing ultraviolet light-stable oxazolidone modified polymers without the necessity of using aliphatic isocyanates. It is another object of the invention to present novel one-package storage-stable polyoxazolidone-forming systems. These and other objects of the present invention will become apparent from the following description and examples.